The universe may end trillions of years sooner than we thought
Scientists have long assumed that our universe would continue to exist for billions of years, but a new study presents a much shorter lifespan for the cosmos: our universe may only last another 33 billion years.
It’s only a cosmic blink of an eye before everything collapses in on itself – a process dubbed the “Big Crunch”, where the expansion reverses, causing all matter and space-time to return to an extremely dense state similar to the conditions of the Big Bang. Although long considered a ruled out possibility for the fate of the universe, due to accelerating cosmic expansion, this new research has reopened this surprising – and slightly troubling – option.
The journey to this dramatic conclusion began with our quest to map the cosmos, where we focused on dark energythe mysterious force that is splitting the universe at an accelerating rate. Recent data from the Dark Energy Survey (DES) and the Dark Energy Spectroscopic Instrument (DESI) have mapped hundreds of millions of galaxies to probe this expansion. These crucial tools suggest, with extremely high confidence, that dark energy’s “equation of state” – its pressure-energy density relationship, which dictates its effect on expansion – is not simply a static number. Instead, its influence seems to change over time.
This strange dynamic opens the door to alternative explanations for the composition of dark energy. This led to the axion dark energy (aDE) model, which proposes that dark energy includes both an axion field, which would be an ultra-light form of dark matter that moves around the universe, plus an axion field. cosmological constantor a fixed background expansion anchored in the structure of spacetime.
In the new article, which has been uploaded to the preprint server arXivthe researchers applied this hybrid model to DES measurements. They found that this combination can probably explain the DES and DESI results, but with one difference: in the distant future of the universe, the interaction of the axion field and the cosmological constant actively brings the universe together, leading to this ultimate Big Crunch.
By taking the model that best matched the observations and running the simulation over time, the researchers calculated a precise time of the cosmic demise: in 33.3 billion years. This considerably shorter future contrasts sharply with the trillion-year lifespan often considered. Instead of a cosmic expansion that expands the universe like a lonely, eternal highway, we get a cosmic U-turn that takes us back to the beginning of our journey.
This is new territory, and while the evidence compels us, the science always comes with caveats. The DES and DESI observations suggesting that the cosmological constant is not static are intriguing, but they still need to be verified. This model depends on many variables, and several different combinations of these could still explain the observations, although a negative cosmological constant – and a resulting Big Crunch – remains the most likely in their analysis.
More data are needed to rigorously test this model. The cosmos is a complicated beast; our understanding continually evolves. As we continue to increase data streams, we are piecing together the greatest story ever told – but that story may end sooner than expected.
